Apparent viscosity has been accepted increasingly by design engineers in sizing pumps and other components of fluid flow systems, such as grease lubrication systems. In general, the apparent viscosity of a fluid is defined as shear stress over shear rate. For non-Newtonian fluids, such as grease, the apparent viscosity changes at different shear rates. The standard method for measuring grease apparent viscosity is defined by ASTM D-1092. Using this method, the apparent viscosity of a non-Newtonian fluid can be measured at different shear rates. However, this method has several drawbacks. The test involves expensive equipment and takes time and effort to run. Further, a separate test must be run for each selected shear rate. Also, the test is not useful at shear rates less than 10 sec−1.